The present invention relates, in general, to powered linear drive type mechanisms for moving an attached object and, more particularly, the present invention relates to a linear drive mechanism for moving a door panel on a rail transit vehicle and, still more particularly, this invention relates to a door operator mounted overhead of a door panel and incorporating a helical drive for moving and supporting such door panel.
Powered overhead door operator assemblies in use prior to the conception and development of the present invention generally employ separate members for moving and supporting the door panel. U.S. Pat. No. 6,422,970 discloses such an overhead operator and U.S. Pat. No. 6,040,697 discloses a self aligning drive nut bracket for use in these assemblies. The teachings in each of the above referenced patents is incorporated herein by reference thereto.
In these arrangements the door drive includes a base plate mounted overhead of a door opening. The base plate includes a separate hanger cavity for housing rollers that are attached to door panel hangers. Such hanger cavity extends along the full length of the base plate. The door drive is located above or to the side of the roller cavity. The drive nut is usually connected to the door panel or door panel hanger via an elaborate linkage to minimize the substantial force generated by offsetting the door drive and door hanger cavity. In addition, the physical displacement between the drive member and door hanger results in additional adjustments of the door panel with regards to motion transverse to the panel plane and hanger cavity axis. Further, the offset arrangement of the door drive and hanger cavity requires larger door operator envelope within the door opening structure.
The present invention provides an overhead linear power door operator for moving at least one door panel of a mass transit vehicle. Such door operator comprising a first operator support mountable overhead of a door opening in the transit vehicle. A drive member is connected to the support at a distal end thereof. An electric rotary prime mover is connected to such drive member using a coupler to power the drive member. Such prime mover is further connected to a second operator support mountable overhead of the door opening in such transit vehicle. A drive nut having an internal threaded bore engages such helical drive member to be driven by this helical drive member upon rotation of such helical drive member by the electric rotary prime mover. There is a driving door panel hanger bracket which extends above such door panel. The door panel bracket is connected to the drive nut. The door panel bracket having at least two upper rollers and at least one lower roller engaging such drive member for motion therealong. A driven door panel hanger bracket extends above such door panel. Such door panel bracket having at least two upper rollers and at least one lower roller engaging such drive member for motion therealong.
Therefore, it is one of the primary objects of the present invention to provide an overhead powered door drive having a single hanger and drive member for substantially minimizing door drive/door panel offsets and wear producing forces.
It is an additional object of the present invention to provide a powered door operator having a drive member of a sufficient rigidity to support the weight of the attached door panel.
It is a further object of the present invention to provide a powered door operator wherein the location of the convex rollers to the drive nut provides a simplified linkage arrangement between the drive nut and door panel.
It is another object of the present invention to provide a powered door operator wherein the location of the convex upper rollers to the helical drive axis provides stability for the door panel.
It is still another object of the present invention to provide a lighter weight powered door operator having fewer parts.
It is yet another object of the present invention to provide a powered door operator utilizing a smaller envelope within the door opening structure.
These and various other objects and advantages to the present invention will become more apparent to those persons skilled in the art from the following more detailed description, particularly, when such description is taken in conjunction with the attached drawings and the appended claims.